...making Linux just a little more fun!
July 2004 (#104):
- The Mailbag
- More 2 Cent Tips!
- The Answer Gang
- News Bytes, by Michael Conry
- Using Windows Keyboard Media Buttons In Linux, by Tom Brown
- How To Make a StereoGram with GIMP, Blender and StereoGraph, by Kapil Hari Paranjape
- Automatic Backups with rsync and Anacron, by Barry O'Donovan
- Songs in the Key of Tux: Audacity, by Jimmy O'Regan
- Desktop Matters!: A guide to Windows technologies for Linux users, by Jimmy O'Regan
- Front and Back: KPGP and GPG, by Jimmy O'Regan
- Inter-Process Communication - Part 1, by Hiran Ramankutty
- Design Awareness, by Mark Seymour
- Taking control of your browsing with Mozilla, by Neil Youngman
- Ecol, by Javier Malonda
- Qubism, by Jon "Sir Flakey" Harsem
- Wonderful World of Spam
- The Linux Laundrette
- The Foolish Things We Do With Our Computers, by Ben Okopnik
The Mailbag
HELP WANTED : Article Ideas
Submit comments about articles, or articles themselves (after reading our guidelines) to The Editors of Linux Gazette, and technical answers and tips about Linux to The Answer Gang.
2.6's constant complaining about untranslated keyboard keys
Mon, 14 Jun 2004 13:02:11 -0700 (PDT)
Bradley Chapman (
kakadu_croc from yahoo.com)
atkbd.c: Unknown key released (translated set 2, code 0x7a on isa0060/serio0).
atkbd.c: This is an XFree86 bug. It shouldn't access hardware directly.
atkbd.c: Unknown key released (translated set 2, code 0x7a on isa0060/serio0).
atkbd.c: This is an XFree86 bug. It shouldn't access hardware directly.
Does anybody get this at all on their 2.6 Linux systems? I get it all the time and have just dismissed it, but now I'm curious if anyone has bothered to figure out why it happens.
Also, I've just got ahold of a Gmail account, but I haven't been able to decide what to do with it. Does anyone else have a similar dilemma?
Brad
getting email from an external server
Mon, 14 Jun 2004 14:30:12 -0400
sbasurto (
sbasurto from playboyunderwear.com)
Good afternoon,
My question is...
I setup an Internet server with debian the lastest version, I also configure a
squid proxy 2.4 estable6 with squidGuard as redirector, a dhcp, a dns, and
ipchains.
The configuration looks like:
190.0.0.3
Workstation|---------|--|
| eth0 -------------- eth1 -----
190.0.0.4 |-|190.0.0.1|Linux Server|192.168.0.1|---|DSL|
Workstation|---------|--| -------------- -----
x.x.x.x |
--------------- Internet |
| Mail Server |--------------|
---------------
What I am expecting - Run send/recive email messages in what ever email client
in a workstation within my lan and get the email from the external server or
send email with the external server.
What is happening - Run send/recieve email messages in Outlook with the right
configuration and it sends a "Conection Refused by the Server" or "Conection
Timeout".I understand that maybe what I am looking for is a pop3 and smtp poxy
server, nevertheless I install pop3.proxy and smtp.porxy servers in my linux
box an it does not retrieve or send the email from workstation to the external
server. I configure fetchmail too an it work but within the server, if I try to
get email from a workstation it crash.
What I already did -
- I already run tcpdump in the eth where the internet conection is (In my case
eth1). In this point I want to mention that in the output of tcpdump I never
saw the header for the retrive of the email message from the
client(Workstation) to the server, nevertheless the conection to Internet is
working fine.
- I also stop my firewall because may be a misconfiguration of the firewall can
block my email, but even without firewall, it crash.
- I installed a pop3 and smtp proxies, and get them run as an inetd service,
but without sucess. I mean the proxy run but can retrieve email from
workstation.
- Finally I had this configuration working with SuSE the problem is that I do
not know exactly how I did it.
At this point I hope some one of you can help me or tell me what I am doing
wrong. Or tell me whatever documentation where I can get an answer.
Regards
Sergio B.J
Scripting languages compared
Sun, 13 Jun 2004 08:34:47 +0100
Jimmy O'Regan (
The LG Answer Gang)
-
[Jimmy O'Regan]
- http://merd.sourceforge.net/pixel/language-study/scripting-language
sh wins, closely followed by Perl and Ruby.
Read that backwards, in terms of winning order and: \o/
-- Thomas
Well, he's wrong about "sh" not having a debugger, particularly since
he's using Bash; "-x" certainly fits the bill. Step-by-step execution,
no, but I think that would go under "full interpreter in debugger".
As to his length comparisons for different programs - certainly in
regard to Perl - he had me cracking up. E.g., the Perl entry for 'env'
has his actual home directory name spelled out...
The rest of it, I'm afraid, demonstrates his lack of knowledge of the
several languages I can vouch for rather than being an accurate
comparison of any sort (he did mostly OK with "sh", though.
-- Ben
Ok, it's your chance, gentle readers. Would anyone like to take a more
thorough and in-depth view about how the languages compare? We come not
to flame Caesar, but to praise him... code samples maybe, but a fair
treatment is called for at the very least.
-- Heather
GENERAL MAIL
Compliments to you all.
Fri, 4 Jun 2004 13:15:18 +0100
Steve Brown (
sp_brown from hotmail.com)
Hi there,
I've just finished reading some of the June issue, I got the feeling that
you are all a little dejected - don't be! You all produce a fantastic read,
absolutely superb - much better than that other one (I did write and tell
them they were crap, but they didn't reply funnily enough).
Thanks, Steve. I don't know that I'd call it dejection - it's more of a
realization of a lot of work ahead, at least for me. Given that I enjoy
it, though, that's no bad thing.
-- Ben
I used to use an Amiga (still own it sans powerpack) and I spent hours and
hours learing to program in C (very very simple stuff), shell scripts and
the like. I loved the learning process and the usability of it all. I was
forced into buying a PC (following the demise of the power pack) and it came
complete with Win95, what a nightmare -I couldn't find out how any of it
worked without paying for the information one way or another. Then I came
across Mandrake 8, actually I was desperately looking for something other
than Windows, and my little world changed. All the information I could ever
want and then some.
One of my earliest discoveries was your good selves. My favourite Amiga mag
was Amiga Shopper - a good mix of basic newbie stuff and more advanced
information - programming, how the machine works and so on. It pandered to
my newbie needs and as I grew in knowledge so I gained even more from the
magazine.
Your magazine offers something similar, a good mix without pandering too
much to the total newbie. So many magazines seem to offer a three monthly
cycle of tutorials with little new material.
I was actually considering recycling a bit of our previous material. Jim
Dennis' "Routing 101" is an evergreen that can definitely stand to be
exposed to new minds; my own Perl and shell tutorials (it turns out that
somehow one of the articles I wrote for it never got published!), too.
Yes, people can find them in the old issues - but I suspect that many of
our readers don't go trolling through the archives but just read us once
a month.
(If anyone's got suggestions on a previous article that's worth dusting
off, my mailbox is always open.)
-- Ben
The only thing I'd like to see is how to build/design a program in for
Linux, don't care what language, just how to design, program and test it, to
give a good correct program.
[grin] See those very tutorials that I've mentioned. I suggest starting
with shell scripting and climbing up from there.
-- Ben
My Amiga programs were very simple, single user
affairs, and I really don't get OOP and multi user stuff yet. I mean how do
you prevent buffer over-runs and memory loss for example.
Those aren't an issue in the modern scripting languages (shell, Perl,
Python, etc.) In C, well, see my response to Tom. Unless you really know
what you're doing, C can be very dangerous indeed.
-- Ben
[Tom Brown]
Tip: If you want to learn how to program in OOP, spend a little
time learning Borland's Delphi (it uses a Pascal variant). It has
nearly all the power of C++, and is easier to use than Visual Basic.
Once you get all the C++ syntax out of the way, you'll learn OOP in no
time. Then you can move on to something like C++, Java, or C#. I had
the same trouble you did, and that's what worked for me.
[Jimmy O'Regan]
You mean Kylix, which is the Linux version. There's also the Lazarus IDE
(http://www.lazarus.freepascal.org) for Free Pascal
(http://www.freepascal.org).
I've snipped a bit of replies that were a sideline about programming
details themselves - with the Gang chiming in, it might make a good
thread or an article in upcoming months.
-- Heather
In the meantime, I shall continue to enjoy your magazine.
Some other thoughts:
Get more people to link to you and advertise your site more, most people
would do it out of gratitude for all the good work you guys do.
Something like that is in process now; it's one of those things that I
mentioned discussing with Heather.
-- Ben
Find every occurence of the .com one and get a link to your site on there as
well - surfers will compare sites and you'll win hands down!
Thanks. A couple of our people were doing just that, right after the
separation.
-- Ben
Take care and all the best,
Steve Brown
Note: I had to use a Hotmail account (yeuchh) as my dog took a fancy to
copper cored wire and ate every single wire sticking out the back of my box,
he only left me with a monitor lead. Next time I'm gonna leave it switch on.
[laugh] If you write it up and send it to me, it'll end up in "The
Foolish Things We Do With Our Computers" column sometime soon.
-- Ben
...and indeed, you can see it here! Any foolish things you've done to
your computers? Send 'em in...
-- Heather
Hi Ben,
thank you for the reply.
I'll keep an eye out for those tutorials. I've got the O'Reilly Learning
Perl Book and I'm still getting over the stage of "it looks like garbage",
familiarity will sort all of that out no doubt. I seem to recall your
one-liner articles, I found those fascinating as they demonstrated the
problem solving methods you use, and gave a good insight in how to use
what's already there.
[Ben]
Actually, I was talking about my 5-part "Learning Perl" series. Take a
look at http://linuxgazette.net/authors/okopnik.html .
Aahh, I'd forgotten about these gems, thank you.
I'm glad to see that buffer overruns etc. are not a problem in Perl or
Python, I'll just avoid C, I'm most familiar with it as a language but it's
some time since I actually used it. Thanks for the example program, I'm
looking forward to looking at that and trying to work out why it isn't
correct.
[Ben]
As Thomas has already noted (something I originally missed due to being
tired and mostly asleep), it's a buffer overflow due to strncpy not
terminating the string - a truly idiotic design decision. From libc's
info:
- Function: char * strncpy (char *restrict TO, const char *restrict
FROM, size_t SIZE)
This function is similar to `strcpy' but always copies exactly
SIZE characters into TO.
If the length of FROM is more than SIZE, then `strncpy' copies
just the first SIZE characters. Note that in this case there is
no null terminator written into TO.
no null terminator oh my.
At that point, as they say, the rest^H^H^H^Hsystem is history...
Nope, I would never have got this, I'll still run the example to see what
happens 'first hand' though.
[Ben]
The actual mechanism, which can be seen by disassembling the corefile,
is a stack smash via a free() call overrun.
jail@Fenrir:~$ gdb -q -c core smash
Core was generated by `./smash
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
#0 0x40096acf in _int_free () from /lib/libc.so.6
(gdb) x/i $eip
0x40096acf <_int_free+191>: mov %eax,0xc(%edx)
(gdb) info reg eax edx
eax 0x34333231 875770417
edx 0x44434241 1145258561
(gdb)
Joel Eriksson did a very impressive demo of getting root with the
above proglet in the vulndev forum. He used Solar Designer's shellcode,
computed the EIP, and pushed the shellcode onto the stack; voila .
This, of course, required the proglet to be SUID. Took ~20 lines of C.
I'm still challenged with a
modem, I've got a HCF modem that refused to work correctly when I upgraded
my motherboard, I'm going to dig it out and play with it some more [grin].
[Ben]
http://linmodems.org
Yeah, my modem used to work, but I just upgraded from a Duron to Athlon XP
on a new board and the modem didn't work correctly, as I had a spare
external modem, although only 33.6 kbs, I used that instead, too lazy to
sort it out. Now my dog's busy digesting big chunks of the power supply I'm
forced to get HCF modem running.
Take care,
Steve Brown.
Re: Dual "Linux Gazette"?
Sun, 6 Jun 2004 13:49:40 -0400
Ben Okopnik (
LG Technical Editor)
Question by God Rudy (Dpfrdtrky from netscape.net)
Hello Linux Gazette and Editor;
[Ben]
Hi, Rudy -
I hope that this is the correct mailbox for my "old" question.
About last december i noticed that "www.linuxgazette.com" changed
it pages drasticaly, to the bad. Through a longer search, i found
"linuxgazette.net" (the "old version").
What happend?
I was reading backissues of both versions trying to find some
answers --> no much succes!
[Ben]
The answer can be found in the cover article that I wrote when we separated
from SSC (the hosts of LG.com) - take a look at
http://linuxgazette.net/issue96/reborn.html . We've actually been trying
to contact readers like yourself, trying to get the word out that the
original Gazette and the original mission are still very much in operation
and going full force; unfortunately, we have not had much success,
particularly since SSC has acted very hostile indeed throughout the entire
process and has supressed any mention of us in their pages.
We still have a large number of readers, mirrors, and translators, but I
wish there was a way to notify people like yourself of the change. If you
have any ideas on that score, please feel free to let me know.
Rudy (just another garden variety God
[Ben]
Aren't we all?
Hello Ben;
Thanks.
Found it! I was expecting something with more "flags".
I was just looking for the wrong thing
Rudy
Re: Foolish things....
Sun, 13 Jun 2004 10:15:00 -0400
Charlie Pearce (
cjp from linuxmail.org)
--- First thing I just want to say, thanks to yourself and the rest of the team
past and present for producing the great thing that LG is. I've just discovered
it and am enjoying reading through the archives
finding many a gem.
Thanks, Charlie! I've forwarded your compliments to The Answer Gang;
they deserve to share in the glory.
Anyway here's my foolish story, feel free to add it to a future issue if you
wish:
[snip] Added to the upcoming issue - we've had enough responses to put
one out this month. --Ben
Re: Linux Gazette Redux :)
Wed, 26 May 2004 13:57:13 +0200
Huibert Alblas (
huibert_alblas from web.de)
Hello Ben (and the others)!
Thanks for your mail,
"das hat mich wirklich gefreut"
(sorry but I don't know how to translate this one to english,
maybe Karl Heinz can help?)
Halb. Welcome home.
-- Thomas
[Ben]
Hey, Halb - great to see that my email has dragged you out of hiding!
According to http://babelfish.altavista.com it translates as "that
really made me happy" - which is a very pleasant sentiment indeed. Thank
you!
[Sluggo]
That's the literal translation, and it works fine. More colloquially
one might say, "It's a pleasure to hear from you."
As far as I know, wirklich means 'really' in the sense of 'truly'
(not falsely), or perhaps 'indeed'. But in sentances like the one above,
'rally' means 'very much'. It comes out to the same thing, but does it
in a different way.
'gefreut' also has a sense of rejoicing and perhaps relief. So it's
more than just 'happy' as in "You gave me a flower and I was happy".
Haven't heard of you and the gang for a long time either.
I was a little bit confused when (over a year ago, as far as I can remember)
I got a mail from (hmm, forgot his name)
claiming he was the editor of the LinuxGazette,
and that he was breaking up with TAG (or something)
Then I stop receiving mails from TAG,
so I thought the Project was dead.
Never!
-- Thomas
Nope, in fact if anything that's why we split - sure looked like the CMS
was gonna kill it.
-- Heather
I visited the LinuxGazette site a few times,
but didn't realy like it.
[Ben]
That would have been Phil Hughes. We broke away from SSC - I wrote a
nice little blurb about it here:
http://linuxgazette.net/issue96/reborn.html
The old TAG list got shut down shortly after that; Phil wanted to
convert the whole site to CMS, which in my opinion would have killed LG
(and for his "version", it obviously has.)
Your experience, interestingly enough, represents my exact viewpoint of
what's happened with many of our readers: those who did not catch news
of the changeover - and if you, a member of TAG, missed it, what does
that say about the average reader? - simply decided that the old LG was
no more. One of the things I'd really like to do is somehow get
through to those readers wherever possible, and in general get the word
out that the Linux Gazette is alive, is publishing, and is better
than ever.
Since then a lot has changed in my live,
At the time of the TAG breakup I was without work,
shortly afterwards I got a job offer at the Metro Group (one of the worlds largest trading companies)
I landet in a Team of 3 people doing Java/Oracle based
Enterprise Portal and Backend Development,
very interseting stuff, but a lot of new stuff to learn.
[Ben]
[grin] In my opinion, that's how any job should be. If there's not a lot
to learn, you're not moving forward. Nobody said that was easy - but
then nothing worthwhile in life is.
I starting to help getting away from usnig winNT based development
to debian.
Opensource is definetly going strong in our litle corner of the company,
Who knows where it will end.
I'm also getting maried next year
[Ben]
Wow. Felicitations to you and your bride, then. Please be sure to give
us a URL to the photos.
Anyways, I just visited http://linuxgazette.net
and saw the the site is "back to normal"
(but looks better!)
[Ben]
Thanks! A lot of credit is due to Rob Tougher who did a wonderful job of
building the CSS. It's been tweaked a bit since then, but he's the man.
I will subscribe to list, but only if it stays below 50 mails/day,
before my subscription was cut there was a lot of noise on the list
from people talking (mainly) to each other.
Then you should be ok -- but bear in mind things fluctuate.
Well, there is a lot of spam, but we're looking into fixing this. And as
for the chatter -- that was due to the move from SSC. There is a bit of
chatter here at the moment, most of which is not Linux related, I
should add.
-- Thomas
One of our threads this month actually was a technical aside to a line
of chatter that began off-topic. You never can tell with the Gang, til
it's all said and done! But, not 50 plus a day, no.
-- Heather
Don't get me wrong, I have nothing against people having fun communicating,
but I won't have the time to keep track of another 50+ mails/day.
I will install the current Gazette on my palm to read on the way home.
Back on topic: Articles.
Yes, we need articles. Please, put fingers to keyboard and type away!
-- Thomas
Have Fun!
Huibert Alblas
You'll be seeing Halb's article soon :D
-- Heather
[Ben]
Right now, I'm actually looking for
ideas on how to get the word out and the direction in which to take LG;
having become the Editor-in-Chief, I now have to take care of the baby -
and I'm a fussy babysitter.
The ideas that have been proposed so far
- making LG a bit more professional to involve the corporate crowd and
advertising in other Linux-related media, as well as a number of other
specific things to do - sound really good to me; however, I'm still open
to input.
You read it here. Gentlefolk, if you've ideas - let us know!
-- Heather
Linux Gazette article in issue 103
Mon, 07 Jun 2004 12:51:10 -0400
C. Numan (
anonymous)
Regarding the PopupALT article.
-- Heather
Jimmy:
I read your article on extensions for Mozilla. Thanks for highlighting
some! I get more and more impressed with what you can do with Mozilla /
FireFox.
I noticed you wondered this at one point:
PopupAlt
Popup ALT does exactly what is says on the tin: it provides a popup of
an image's ALT tag when the mouse is placed over it. This feature, which
was present in Netscape 4, was removed from Mozilla for some unknown
reason.
I believe it was taken out since the correct HTML spec says the alt tag
is only to be displayed if the browser can not display images. It is not
supposed to be a "pop up" info. I couldn't find it, but I think there is
some tag to display a pop up when the mouse hovers.
[Ashwin N.]
The "title" attribute in the "img" tag is shown as popup text by most
browsers when the mouse cursor is hovered over the image.
<img src="your_image.jpeg" title="This should show up when you hover your
mouse over this">
Anyways, it is a cool extension to show the information, but Mozilla as
default is now more correctly rendering the page. In fact, the W3 says
that the alt tag should be used very carefully, and I've seen some
really long alt tags - this causes problems if your browser translates
to voice or braille, which is the purpose for the alt tag.
See: http://www.w3.org/TR/html401/struct/objects.html#alternate-text
Just thought you might be interested in some of the history.
C.
linuxgazette.net down......
Thu, 3 Jun 2004 22:50:02 +0200
Martin Bock (
mbock-stade from t-online.de)
Hi folks,
you've asked for it, you'll get it: A few thoughts of my own about
missing mail to TAG.
- The "average" PC user today differs from the average PC user three or
five years ago. Today there are a lot of more people using computers at
work or at home. The majority of these peoples are interested in doing
stuff like writing mails and letters, surfin' the web and other
non-sophisticated stuff like this. Most of them feel no need to find
out why things work for them and how they could could customize or
improve something.
- There are a lot of distributions around, which install with a few
mouse clicks a usable system. There is no need to think (and ask) about
partitions, filesystems, configuration and so on. In most cases there is
no need to edit files e.g under '/etc/ppp/' - it's all done by
${install-tool} with drop-down- and dialog-boxes.
- Linux is grown up -- there are lots of information around (at? on? I
dunno) the internet. Best of it: They are only one "google" away.
I appreciate the project "Linux Gazette" (hey, there are all issues from
the beginning on my workstation's and my laptop's hard disks). But: I
feel, nowadays Linux Gazette shouldn't focus on basic- and
newbie-support, but should do more stuff one ore two steps further.
BTW: The link on my site points to your (true[tm]) Linux Gazette.
Keep on rollin ...
Nice Regards
Martin Bock
GAZETTE MATTERS
Asking 2c-tips of TAG
Mon, 24 May 2004 20:37:26 +0100
Thomas Adam (
thomas_adam from bonbon.net)
I am a little bit concerned the people here (especially those that are
more established) don't fully understand what constitutes a 2c-tip. A
2c-tip is just that -- something that is short and easy and can be done
in a few steps. Asking whether it is appropriate (Neil!) just causes us
more grief to wade through meta questions!
This might be in the form of a configuration tweak, or a minuture
program that performs a given task, etc. Often though, larger tips are
turned into TAG column entries -- and vice versa.
Often what would be flagged by Heather and I as a TAG entry might well
form off-shoots to 2c-tips if the quality of the thread in question is
not worthy.
But we will publish anything not only explicitly marked as a 2c-tip, but
also what we deem appropriate to be one. We certainly don't filter out
sent in tips -- only vary rarely. The only thing I will say to you is
that don't always expect to submit one and see it in the preceeding
release of LG. Heather and I decide which tips get published when.
[jra]
If you can figure out how to publish tips in an issue of LG that's
already gone out, my hat's off to you, Thomas.
[Ben]
The method is covered in Jim's "Retro" series. It's based on that
capability of Linux that Linus talked about, executing an infinite loop
in three seconds...
[Jason Creighton]
Yes, it's quite a clever method. Instead of going to all the work of
updating every copy of the LG everywhere, we just insert the tips in the
past before all the mirrors pick up the issue.
The one problem is that executing an infinite loop in three seconds can
only place information in the future. In order to place it in the past,
we must use a Windows box, which, as everyone knows, takes an infinite
amount of time to execute a three second loop.
Send them in.... you know you want to.
-- Thomas Adam
Author FAQ...
Wed, 23 Jun 2004 09:11:30 -0400
Ben Okopnik (
LG Technical Editor)
...is now updated:
http://linuxgazette.net/faq/author.html
Thanks to Jimmy for doing a lot of the preparatory proofreading.
Comments, corrections, and ideas welcome.
Licensing
Fri, 18 Jun 2004 08:47:35 -0400
Ben Okopnik (
LG Technical Editor)
[Ben]
OK, I've done my bit of research and rewrite, etc., etc., etc. - thank
you, Rick and Jimmy, for contributing to my knowledge of the topic.
If you readers think that discussion might be interesting to you, let us
know. Most of the Gang here found it rather dry.
-- Heather
[Ben]
I've decided that the OPL is a good license for us to stick with, as
long as the optional stuff is not asserted; consequently, I've updated
our <http://linuxgazette.net/copying.html> page - it was a) in the "old"
LG format and b) showed the draft version of the OPL. Both are now
fixed. Starting with the next issue, the front page will now explicitly
state
All content released under the Open Publication License v1.0 (options A and B not applied)
and the individual articles will be tagged with
Copyright © 2004, [author_name]. Released under the Open Publication license
Comments, as always, are welcome.
[LG 101] mailbag #2 - Stephen Bint
Mon, 7 Jun 2004 11:22:35 +1000
Peter Maxwell (
peter.maxwell from anu.edu.au)
Question by gfa2c (gfa2c from gmx.net)
Stephen Bint died in February. I wouldn't have known except that back
then google turned up his sister's web log:
http://www.livejournal.com/users/smaoineamh/2004/02/27
http://www.livejournal.com/users/smaoineamh/2004/03/06
Apologies is this is old news (after all you published the question 2
months ago) but I guess it is just possible that no regular Linux
Gazette readers were able to help.
-- Peter Maxwell
We sorrow that he's gone, but he stuck to his principles. There's
plenty to be said for that.
-- Heather
This page edited and maintained by the Editors of Linux Gazette
HTML script maintained by Heather Stern of Starshine Technical Services, http://www.starshine.org/
Published in Issue 104 of Linux Gazette, July 2004
More 2 Cent Tips!
See also: The Answer Gang's
Knowledge Base
and the LG
Search Engine
a question about linker script
Ben Okopnik, Jimmy O'Regan, Philip O Brien (
The LG Answer Gang)
Question by Liang Jun-Ming (helo54ljm from yahoo.com.tw)
Dear Mr.Okopnik
My name is Liang Jun-Ming,a student from Taiwan.
I'm suffering from a programming problem,I would very much
appreciate receving an answer from you !
I wrote a testing program named hello.s , and a linker script named
ldscript as follows:
See attached liong.hello.s.asm.txt
after " as hello.s -o hello.o" and "ld -Tldscript hello.o -o hello"
I get an executable named hello.
My question is:
What does "AT(0x3000000)" mean ?
Does it mean that the loader will load this executable at
"physical address " 0x3000000 ?
I know the "virtual address" of the first byte of this executable
would be 0x1000, but in Linux , can we put data at any physical
address as we wish ? If it does, why the program still works even if the RAM
is 32M in my PC ?(0x3000000 > 32M). What tool in Linux can we have to
let us "watch" the contents of memory by specifying "physical addresses"?
If it doesn't, what is the function when we write "AT(xxxx)" ?
Hope I can receive an answer when you are not busy. Thank you very much!
[Ben]
Hi, Jun-Ming -
I'm afraid your question is somewhat misdirected: I'm not an assembly
expert, under Linux or otherwise. My suggestion to you would be to start
at http://linuxassembly.org and go from there - their front page
reads
|
...............
Welcome to the Linux Assembly!
If you are looking for information on assembly programming under
UNIX-like operating systems (Linux/BSD/ BeOS/etc), this is the right
place to be. Here you can find various resources, ranging from tutorials
and documentation, to actual programs written in assembly language. As
time passes, we will try to provide as much information on the subject
as possible, so stay tuned.
...............
|
That seems like the right place for your query.
[Jimmy O'Regan]
The AT() keyword is for things like ROMs. I recommend you read the GNU Linker manual:
http://www.gnu.org/software/binutils/manual/ld-2.9.1/html_chapter/ld_3.html#SEC21
Dear Answer Gang:
According to the GNU linker ld manual:
the AT() keywod specifies the load address of a section,
and it says "this feature is designed to make it easy to build a ROM image..."
Query,
- the address specified by AT() keyword to load is the "physical address"
of ROM ? and we can really put code in ROM in this way ?
- the "ROM" the document mentioned is the actual element in board, or
just RAM of imitating the Read-Only-Memory ?
( forgive me for a Chinese student's poor English !)
[Jimmy]
The AT() keyword can be used for ROMs - if you want to write a
replacement BIOS (such as Linux BIOS: http://www.linuxbios.org), you
will have to do use the AT() keyword; or if you are creating a ROM
images for later use in an emulator, or to write to a physical ROM.
You can also use the AT() keyword for boot loaders/kernels, which need
to be at a specific location in RAM to be executed; and in a normal
program. If the program has a specified load address, and is loaded on
an MMU-less system, or in an OS which doesn't use the MMU, then you get
access to that specific area of memory, but in an OS (such as Linux)
which makes use of the MMU, the address is transparently remapped to an
address within the space allocated to your program by the kernel.
Jimmy also asked a friend...
-- Heather
[Jimmy]
Sorry about the format this takes; I asked a friend from college if he
could answer the linker script question, the answer is in the attached
IRC log. There's a lot of overview in there which I thought was
interesting. Philip's credentials are that he wrote an operating system
for his degree thesis, based on KeyOS (http://keyos.sourceforge.net),
to which he contributed code under a pseudonym (the college made some
claims about copyright...).
Logged from the
UnderNet IRC
on Jun 20.
-- Heather
|
...............
<JimRegan> So, can you answer that question?
<JimRegan> Cos noone at LG can.
<Crypty> question?
<JimRegan> In the html file I sent
<Crypty> its the offset that that section is loaded at.
<Crypty> the offset from the loadaddr
<JimRegan> ?
<Crypty> and the 0x1000 is the size of the section if i remember correctly
<Crypty> or at least i think thats it.
<Crypty> had to figure it out for writing my boot loader, which i couldnt get to work right, caused fatal exception when it switched to ring 0 to enter PMODE.....
<Crypty> ended up having to use Grub, but handed up my effort to the examiners, they were impressed i got it to ge tthat faer.
<JimRegan> So... in a ROM, it'd go from the beginning of memory, otherwise it's relative to where it loaded
<JimRegan> If the ROM is loaded at 0
<Crypty> .text is actually the code by the way, not the strings.
<Crypty> and yes, but all programs see their address as 0, but the OS handles their requests for memory locations and adds their offset in the memory manager
<JimRegan> The strings go in .data
<Crypty> yes
<Crypty> the code is put in a large offset to avoid overflows causing mistooks in the code.
<JimRegan> So it's not necessary to specify the location, unless you have some weird backwards compatibility problem, or are writing an OS?
<Crypty> but the OS can preempt this and actually fool the program by pretending it loaded the code at that offset and translating the addresses on the fly
<Crypty> well, it is also to specify locations in writing an OS or other "pure application"
<JimRegan> So, in short, you can't just put code wherever the heck you want in a modern OS?
<Crypty> but a decent OS will just ignore the offsets and pretend instead
<Crypty> no, the OS itself has to obey the offset rules, as the memory manager will not be loaded at that point.
<JimRegan> I mean if that's executed in a running OS.
<Crypty> so it cant pretent and every thing is relying on exact offsets for a form of crude task switching.
<Crypty> oh, yes.
<JimRegan> Like the MacOS did?
<Crypty> but even without a ld script, it should still use a default set of offsets for linking, depending on ythe executable format, coff, elf, bin etc..
<JimRegan> OK, I think that'll answer the question. Do I have your formal permission to send this for potential publication?
<Crypty> the offsets are set by default on set types of exe, so that the os can just go , heh I know this type, and not have to search for markers in the code etc.
<Crypty> no, hehe I better read up and make sure its right first.. its been over a year.
<JimRegan> Ah. Cool.
<JimRegan> Well, what you've said makes what I read in the LD manual make sense.
<Crypty> oh well in that cvase.. sure.. just dont sign my name to it, klast thing i need is people with questions :-) or worse some git flaming me for not getting it quite right.
<JimRegan> AT ( ldadr )
<JimRegan> The expression ldadr that follows the AT keyword specifies the load address of the section. The default (if you do not use the AT keyword) is to make the load address the same as the relocation address. This feature is designed to make it easy to build a ROM image. For example, this SECTIONS definition creates two output sections: one called `.text', which starts at 0x1000, and one called `.mdata', w
<JimRegan> hich is loaded at the end of the `.text' section even though its relocation address is 0x2000. The symbol _data is defined with the value 0x2000:
<Crypty> but that said I think i got it right, been a while but I think i remember it right
<Crypty> oh, good I did remember it right.. yeah, go me!
<JimRegan> So, do I get a definite OK now?
<Crypty> hehe I am still one of the knigits of ye olde ASM coding :-)
<Crypty> yeah sure.
<JimRegan> Thanks.
<Crypty> you can tell me if some one flames you for getting it slightly skew ways,
<Crypty> but it is a good enough explainatin to the question i think
<JimRegan> Nah. People are generally polite in pointing out mistakes.
<JimRegan> God knows I've made enough of them.
<Crypty> AT() is definitly the offset it gets loaded at and the x1000 is the size of the section, they are seperate in that one specifies properties of the process after its loaded and one specifies properties of the EXE.
...............
|
Launching Firefox 0.9
Raj Shekhar (
rajshekhar from hotpop.com)
Hello
I had used the following script for launching Firefox (earlier named
firebird) (See my article Mozilla Firebird - A review
(http://linuxgazette.net/issue97/shekhar.html) to see how you can use this).
#!/bin/sh
/usr/lib/mozilla-firebird/MozillaFirebird -remote "openURL('$@', new-tab)" ||
exec /usr/lib/mozilla-firebird/MozillaFirebird "$@";
However, with the 0.9 release (the latest one, which is even more slick
and fast), this stopped working. Instead of launching the new tab, the
Profile Manager UI pops up. This was reported as bug
http://bugzilla.mozilla.org/show_bug.cgi?id=246168 in the Mozilla Bugzilla.
The reason for this is the change in the format of calling the remote
command. The new way of doing this is:
firefox -a firefox -remote openURL(<url>,new-tab)
Note that there should be no space between the the comma and the command
after the url (new-tab in this case, you can also use new-window to
start a new window) or you get a "Error: Failed to send command: 509
internal error".
So the script to launch firefox becomes
#!/bin/sh
/usr/lib/firefox/firefox -a firefox -remote "openURL("$@",new-tab)" ||
exec /usr/lib/firefox/firefox "$@";
[Ben]
I just had the same problem with the new Mozilla upgrade; the trouble is
in the brain-dead URL parser at the end of the wrapper script. Although
I fixed it, it very quickly became useless: I downloaded Mozilla 1.7 from
http://mozilla.org, and its wrapper script works fine.
Oh, and since you brought this issue up: just yesterday, I was reading
about Mozilla's "remote" methods in order to fix the above problem - and
still forgot, completely, that there's a "native" way to test if Mozilla
is running or not.
Wonder if I can trade this brain in for a newer model?
mozilla -remote "ping()" 2>/dev/null && mozilla -remote "openurl($1,new-window)" || mozilla $1
Checkinstall
Neil Youngman (
neil.youngman from wirefast.com)
This one courtesy of LWN. You want to build a package from the latest
source, but have it managed by your favourite package manager.
Checkinstall claims to automate the process for Debian (presumably any
system using dpkg?), Slackware and RPM based systems. I gotta have it
http://checkinstall.izto.org
Publication by LWN is hereby permitted
[Thomas]
I have used both, and my personal preference would be the use of
stow
over checkinstall.
Typing stow as a keyword into the search box at freshmeat.net also
reveals some interesting competitors, and a front end for stow.
Also, Allan Peda had an article on this topic in Issue 75,
Simple Package Management With Stow
-- Heather
Periodic table of the operators
Jimmy O'Regan (
The LG Answer Gang)
One for Ben: a periodic table of Perl 6's operators.
http://www.ozonehouse.com/mark/blog/code/PeriodicTable.html
[Ben]
"Today, we're going to learn about one of the varieties of serious
mental disturbance. Here, for example, is a distinctly pathological
case..."
It's got some amount of cuteness to it, but I think you'd have to be a
bit obsessed to actually do the thing up. Reminds me of an excellent
model of the Titanic, about 8' long IIRC, built out of matchsticks - all
the way down to the deck chairs and the oars in the lifeboats - that I
saw at an exhibition of artworks done by mental patients. Much of the
work was incredible, brilliant, and unrepeatable in many cases - and the
stories (such as that of a woman who made these shockingly beautiful
patterns from threads she'd pluck out of rags... and almost all of whose
work had been thrown away because it was just "trash" made by "crazy
Nancy") would break your heart.
"Remote" authentication with PHP
Lew Pitcher (
lpitcher from sympatico.ca)
Hi Guys
Here's another contribution. Hopefully, you can publish it as a 'two cent tip'
As part of a PHP web app I'm playing with, I needed to authenticate the web
client user with a remote system. Unfortunately, this system is a mainframe
and setting up a web-enabled authentication product on it is somewhat
timeconsuming and requires a lot of administrivia. I wanted to avoid all
that, so I had to come up with another way to authenticate web users
remotely.
The one TCP/IP networked app our mainframe has available is FTP. Now, the FTP
protocol implements security processes with the 'USER' and 'PASS'word
commands, and our host security people have ensured that the host FTP server
requires these two functions. In our case, the 'USER' and 'PASS' functions on
the server interface with the ACF2 security system to validate that the given
userid and password combination are correct, and will not let an FTP
connection in if they aren't.
I use this little tidbit of information to let me authenticate web users of my
Linux box by forcing their web browsers to pop up the Authentication panel,
and sending their entered userid and password information to the host in an
FTP 'USER' and 'PASS'word command sequence. If the host's FTP rejects the
sequence, then the user isn't authorized, but if the host's FTP accepts the
sequence, then the user is valid to the host. In either case, I don't
actually transfer files over the FTP link; I simply close it unused. I only
need it for the authentication.
Neat or what?
Here's an example PHP script that demonstrates the process. It needs an
ftp server in order to work, and is (for demonstration purposes) set up to
talk to the ftp server at localhost...
<?php
/*
** LoginPrompt() sends headers and html with the intent of
** inducing the web-browser to display it's built-in userid/password
** prompt.
** It sends a WWW-Authenticate header to give the authentication specs,
** a HTTP 401 on the current page requested by the browser, and
** a dummy HTML page to be displayed if the user cancels the
** login prompt
** It then exits, causing php to terminate the current transaction
** without further output
*/
function LoginPrompt($URL)
{
/* force the login popup to show up */
Header("WWW-Authenticate: Basic realm=\"System Login\"");
Header("HTTP/1.0 401 Unauthorized");
/* if the user hits Cancel, send him to a place he cant hurt us from */
echo "<meta HTTP-EQUIV=\"Refresh\" CONTENT=\"0; URL=$URL\">";
exit;
}
$userid = $_SERVER['PHP_AUTH_USER'];
$passwd = $_SERVER['PHP_AUTH_PW'];
$validuser = "no";
if ($userid && $passwd)
{
/* connect to FTP server, see if it accepts the given userid & password */
$conn = ftp_connect("localhost") or die("Cant connect");
if (@ftp_login($conn,$userid,$passwd)) $validuser = "yes";
ftp_close($conn);
if ($validuser == "no") /* bad user - try the login again */
LoginPrompt("http://www.php.net/manual/en/features.http-auth.php");
}
else /* first time into this page - force the 1st login prompt */
LoginPrompt("http://www.php.net/manual/en/features.http-auth.php");
phpinfo();
?>
Xserver spits Xclient hosts
Chris Christensen (
Chris.Christensen from aspenresearch.com)
This is in reply to:
http://linuxgazette.net/103/lg_tips.html#tips.4
-- Thomas Adam
Regarding Xserver spits multiple windows to foreign Xclient:
I have no knowledge of Exceed. I use cygwin to connect to unix/linux boxes.
You have to configure/install cygwin with X (and ssh, if you're going to use
that, and why not?). Crucial step is to start an xwdm (blackbox I think,
whatever is available on Cygwin) first, and start linux x-apps from inside the
xwdm (start with an xterm!). The full screen x-windows display manager is
actually running locally, while the windowed apps are in the dm.
Chris C
Fun game in 64 LoC
Ben Okopnik (
LG Technical Editor)
Ambassador of Pain - quite entertaining for 64 lines of code. (That's in
C, mind you; if it was Perl, I'd be expecting Quake3, including the PAK
file.
http://raffi.at/view/code/aop
Grokdoc
Jimmy O'Regan (
The LG Answer Gang)
A while back, Groklaw mentioned that they wanted to have a Linux
usability test, and technical documentation written for new users.
They've started a wiki (based on the Wikipedia software) to do this:
http://www.grokdoc.net/index.php/Main_Page
This page edited and maintained by the Editors of Linux Gazette
HTML script maintained by Heather Stern of Starshine Technical Services, http://www.starshine.org/
Published in Issue 104 of Linux Gazette, July 2004
The Answer Gang
...making Linux just a little more fun!
|
The Answer Gang
By Jim Dennis, Karl-Heinz Herrmann, Breen, Chris, and...
(meet the Gang) ...
the Editors of Linux Gazette...
and
You!
|
We have guidelines for asking and answering questions. Linux questions only, please.
We make no guarantees about answers, but you can be anonymous on request.
See also: The Answer Gang's
Knowledge Base
and the LG
Search Engine
Contents:
- ¶: Greetings From Heather Stern
Linux says "unknown scancode" for all keys
- Suggestions for *low* end systems?
- software CD player does not play thru speakers (Linux RH 9, Dell Dimension 2350)
- Mixing Fvwm with applets
Greetings from Heather Stern
Greetings, folks, and welcome once again to the world of The Answer Gang.
Statistics, hmmm... things are starting to look up... still want poeple to get the word out though. The real Linux Gazette is over here at .Net. Tell your friends.
No real peeves with our querents this time, so we have the belly laugh of the month instead - a piece of spam telling us what a great deal we can get on free unlimited technical support. Whee!
Thomas and I have been busy, and not just onanking away on pubbing the TAG mail. We've had quite a happy time chatting with each other now that we've gotten voice over IP working. It was a rocky road though...
Lesson Zero. Get sound working on your own. If you can't hear linus torvalds talking or your favorite musical strum or a nice little MP3, don't hold your breath that you'll hear anything on the "phone" either.
Lesson One. Thou shalt have a working microphone. One that you have to solder back together will not cut the mustard (but it will cut in and out even when everything else works). He got a nice cheap deal for one finding on online special. I got a nice echo canceling one built into my headset.
Lesson Two. Thou shalt plug they speakers or headphones into the right holes on the soundcard. Otherwise they don't make much noise. Whoops.
Lesson Three. This mainly affected him; I have a static IP and correct reverse DNS to go with it - but VOIP hates network address translation. Hates hates hateses the nasty NATses. Rumors that kphone has figured out a way to deal with this couldn't be tested because if it does, it's specific to that one app, and while kphone likes his box fine, it hates me, crashes (should that be krashes?) in moments after launch. Hmm. Rumors of the ease of use of SIP applications have been exaggerated... or they don't survive NAT either.
Port forwarding was tried without success, because he has a windows box speaking to his cablemodem, thanks to the brain damageed code it needs to make a connection. The Linux support for that device is starting to shape up, though.
Meanwhile, Gnomemeeting did the trick. As long as I've already launched (so my client goes and registers with an LDAP database out there somewhere) and he initiates the call (little hard to reach his Linux box directly with the NAT) then it handles all the gory details.
We had to mess with codec for our voices too. I hear his voice fine when I set speex-15k. He likes what he hears of me when he sets Alaw. This doesn't make much sense to me, since in theory both of these are just beyond the scope of our rated bandwidth, but it works anyway. So don't take its recommended limits for gospel - goof around, try all the codecs.
For long distance project work with a bunch of people, IRC works great. Wikis are pretty good too (check out that Wikipedia, our Answer Guy has grown very enamored of it and is helping out on a few topics). I'm pretty pleased with how my upgrade to my own SysadMoin worked out. But for working with only a person or two at a time, sometimes chatting directly can cut through confusion - "body language" carries a lot better in voice than emoticons - and give more time for brainstorming. Or being silly, as the case may be. We can split ginger beers and laugh about Ben leaving his dark glasses in the pretzels again.
I think it's a pretty good way to celebrate Independence Day - hands free and proud! Have a happy Summer.
Linux says "unknown scancode" for all keys
From Justin Ekis
Answered By: Thomas Adam, Karl-Heinz Herrmann, Benjamin A. Okopnik
Hello
I went to look at the kernel messages with dmesg today, but surprise!
All that I got was line after line of this:
keyboard: unknown scancode e0 64
dmesg and /var/log/messages are just about useless, flooded with that.
It's the same scancode every time too.
the command showkey -s shows that my wireless keyboard does send an
extra scancode after each key along with the normal scancodes. This is
apparently some kind of status notification. I was surprised that the
keyboard worked at all since it required a special driver under Windows
so I almost expected something like this.
[Thomas]
You did not tell us which distribution you are running. Not that it
really matters, but each distribution has a slightly different way of
handling console keymaps.
Oh yes, sorry. I'm running Slackware 9.1
[Thomas]
You should ensure, regardless that:
/etc/console/bootmap.gz
is correct, but I suspect it is since you were able to write us the
e-mail.
If you're running debian, it is just a case of doing:
dpkg-reconfigure console-data
However, your errors are usually indicative that your keyboard mappings
are off. The only thing I would have suggested is that you used loadkeys
and dumpkeys, and if that doesn't work to define the keycodes yourself,
via keymaps and setkeycodes(
.
Strange, there is no directory called /etc/console here. I'm sure my
keymap is good though. Other than the warning the keyboard works
flawlessly and it doesn't happen when I use a standard keyboard. I
prefer my wireless one though.
[K.-H]
Well -- I've no idea how to change the keymap -- but if the keyboard is
basically working and the only annoying thing is the flooded syslogs how
about dropping these messages? As what kind of syslog messages are they
logged? kernel? info level or higher? The old syslogd has restricted
options to accept or dump messages of a particular type (not content
filter). I know that SuSE 9.x offered a new improves syslogd as an
alternative -- so that might even be able to do some fancy filtering on
the message content (and dump your keycode warning). Won't help for the
boot-log but /var/log/messages won't be floded anymore.
To read the boot log /var/log/boot.msg without the garbage you can run
grep with negative filter like:
grep -v "your keycode" /var/log/boot.msg | less
The keyboard works but I don't like my log being made
so huge by all that junk.
I went to look at the kernel messages with dmesg today, but surprise!
All that I got was line after line of this:
keyboard: unknown scancode e0 64
dmesg and /var/log/messages are just about useless, flooded with that.
It's the same scancode every time too.
[Ben]
I just had a similar problem, although it wasn't a flood as it is for
you; perhaps 10 of these messages every hour. Before I could get around
to fixing it, I upgraded my kernel from 2.6.3 to 2.6.5 - and the problem
went away. So, even though I can't take credit for finding the solution
(or even the exact problem), there it is.
The "scan codes", as far as I could tell, were being generated by some
kernel driver seeing a signal from a piece of hardware with which it
wasn't completely familiar and spitting out the unknown signal as a
"scan code". In my case, I'm pretty sure that it was the new Synaptics
touchpad - which definitely required a new driver.
Suggestions for *low* end systems?
From tag
Answered By: Thomas Adam, Jay R. Ashworth, Jimmy O'Regan, John Karns
In all the years of installfesting, hackery, hints, and consulting, I
get a lot more questions from ordinary folk about how to make last
years... or sometimes last decade's... hardware run half decently rather
than walk with a limp.
Lots of articles I see about the latest and greatest, or what K and
Gnome have improved for everyone this season, just aren't too useful
to folks buying a laptop at the local surplus shop though. Low memory
is almost always a more painful limit than low CPU oomph, though that
too, is a factor.
[Thomas]
Well, let's see. My P166, with 32MB RAM ran X11 (version 3 and 4) not
too badly. Granted, it wouldn't run KDE or GNOME, but if you were
patient, it would run X, and you could get somne usability out of it....
What helped were a number of things:
1. A low resolution colour-depth (8/16 bits) is always a good idea. This
frees up quite a lot of memory. Usually a high colour-pallet is only
ever needed if you're a gamer -- and that just isn't going to be the
case on the sort of hardware you're referring to. Some window managers
(fvwm is one such window manger) allow you to set this, aside from the
defaults set by the X-server.
2. Using a window manager (hellllo, "fvwm"
) as opposed to a desktop
environment is preferable. This means that interal cruft such as built in file
managers are external and hence loaded only when needed. This helps
to reduce memory consumption until such application need to be invoked
which may be never. And even then, if a GUI file manager is needed I'd
recommend 'emelfm'.
3. Using an alternative to X11 pure might be an option for really
low-end specs. Such things as: TinyX, mgr (yay, I love mgr, although
sadly archived) and even Y-Windows (yes, I have named that right).
[Thomas] There is also the RULE project, which is probably best just for this
scenario where low-end hardware is being used. "Run Up to date Linux
Everywhere" is excellent.
http://www.rule-project.org
[Jay]
And don't plan on running FireFox unless you're willing to compile it
yourself. :-}
[Thomas]
That wasn't in existence back then. I was using netscape 4 at a push. I
did help with LFS -- it took five days straight to compile XFree86 3
I kid you not....
[Jimmy]
Software designed for handhelds is probably the best bet. Aside from
kdrive/Tiny X, there's
Nano-X/Microwindows: http://www.microwindows.org
Twin: http://linuz.sns.it/~max/twin
OpenGUI: http://www.tutok.sk/fastgl
MiniGUI: http://www.minigui.org
PicoGUI: http://picogui.org
Nano-X is somewhat X compatible, Twin is curses based, and PicoGUI will
run on Linux on the Palm. Even OPIE will run in 10 megs of RAM.
[Heather]
If they're in a networked environment, there's always letting a tougher
machine do some of the work (hellloooooo LTSP) but that's cheating.
[John]
That was my thought too. One thing I would add is to check out the
Knoppix Cluster release / edition. I ran into a real snag with plain LTSP
when I trying to implement a diskless cluster network, where the main app
of interest was in MM flash. The 3.x version of LTSP didn't support any
version of Mozilla, or Netscape later than 4.x via the incorporated
busybox pkg. I managed to resolve that issue, but was unable to resolve
the problem of having the LAN bw eaten by the flash animation, by getting
the browser to run locally in the slave memory rather than on the server.
After about 8 instances, the (100 mbps) LAN came to a crawl. We ended up
succombing to adding hd's and running as normal hosts
. Sometime later
I discovered that the Knoppix cfg overcomes the problem by running all
apps in the local nodes RAM. I believe that Knoppix uses LTSP, but has it
configured to do what I couldn't get it to do. Some day I'll take a look
to examine the LTSP cfg that Knoppix uses.
software CD player does not play thru speakers (Linux RH 9, Dell Dimension 2350)
From Ted Kubaska
Answered By: Thomas Adam, Jason Creighton
I'm having some difficulty getting my CD player to play through my
speakers. I have a Dell Dimension 2350 running Red Hat 9. I got this
Red Hat 9 by downloading the ISOs from the Red Hat site. When I bring up
the saw CD player, the screen comes up, I can see the elapsed time tick
by, but there is no sound coming from my speakers. I can plug into the
headphone jack on the CD drive and get sound.
[Jason]
The problem is probably the fact that there's actually two ways to play CDs.
One way is for the software to just tell the CD drive to start playing: The
sound will play in the little jack on every CD drive in existance that nobody
ever uses anyway. There's also supposed to be a cable running from the CD
drive to the soundcard inside a computer, which is how things work normally.
[Thomas]
While this is true, this is only applicable if you're using a CD-Player
that extracts sound using analog. While most do, Windows applications
don't (Media-Player being an example). For the case of laptops, sound is
extracted using raw audio.
[Jason]
So the sound never actually gets to the software. And in this case, the sound
never actually gets to the sound card because a connection is obviously
missing on your laptop.
The other way to play CDs is read the CD "raw" and then just send the sound to
the sound card.
Some software tries to do it one way, some the other.
Try this:
$ play -t cdr /dev/hdc
[Thomas] In more recent versions of play(1), if you're using ALSA, you must tell
it so.
[Jason]
where /dev/hdc is whatever your CD-ROM drive happens to be.
Thanks. Jason's explanation of the two ways to play CDs clears up a lot
of confusion. I have succeeded in getting my CD to play thru my speakers
(with xmms, not the CD player that comes up with RED Hat -> Sound &
Video -> CD Player).
I have not yet taken the skins off of my Dell Dimension 2350 (this is
not a laptop as some thought, but Dell's low end tower, a 2 GHz P4) but
will do so after the mail I got. Just to check the cable people have
referred to. From what I read so far I think my sound card is integrated
on my motherboard and not actually a separate card. The RedHat Hardware
browser says 82801DB AC'97 Audio, Mfg Intel, Driver i810_audio.
[Thomas] i810_audio is courtesy of Intel and probably at the time this was
written was still quite new. It's certainly not the best soundcard out
there (or should I say embedded chip) but it does the job quite well.
I issued a play -t cdr /dev/cdrom and a play -t /mnt/cdrom and got no
response at all.
[Thomas]
This is because "/mnt/cdrom" in this context doesn't point to anything.
One does not mount audio CDs and so the actual device (/dev/cdrom) must be
used.
I was pointed to an earlier TAG discussion
http://linuxgazette.net/issue80/tag/4.html
From the information there I downloaded xmms-cdread-0.14a.tar.gz from
ftp://mud.stack.nl/pub/OuterSpace/willem, unzipped, untarred, built and
installed. I am now listening to CD output thru my speakers!
[Thomas]
This method is still using audio-extraction which often makes the CD-ROM
drive spin around very fast. This can be quite noisy, especially on
laptops.
All is not perfect, however. If I put in a new CD, the default CD player
starts up automatically. This player does not work and never has. I have
clicked on preferences for this player (the knife and fork icon) in an
attempt to not have it load automatically. I specified no action on CD
[Thomas]
You don't say what window/desktop manager you're using, but if I recall
correctly. RH9 uses GNOME as the default desktop manager. It's possible
that the settings were/are not saved until you logged out...
load; but it still comes up and tries to play when I load a new CD. I
see the elapsed time tick by and get no sound thru the speakers. I have
to kill this player and bring up xmms, click on play, and then all is
well.
[Thomas]
This comes back to what Jason and I said earlier about how audio is
extracted. Since XMMS defaults to using Raw audio, and other players use
analog, without the use of such a cable, you just won't hear any sound.
Mixing Fvwm with applets
From John Karns
Answered By: Thomas Adam, Heather Stern
Hey, another fvwm user! BAC, Thomas, have you experimented with running
windowmaker applets under fvwm? I really like a lot of the applets WM
offers, (e.g., wmmount), but can't seem to get it to work inside of
the fvwmbutton module.
[Thomas]
Yes, I have. If you're running them from within FvwmButtons, that puts a
slightly yet subtle slant on how things are done, since you'll have to
ensure that a few conditions are set.
That seems a much better way than having small 48x48 pixel windows
scattered around the root window. One alternative might be to use the
WM docking window (if that's the right term), but I would still prefer
the fvwm buttonbar (or whatever it's called). Might there be some
other nice(i.e., esthetic) way to gather them?
[Thomas]
Because the WMapplets are from another Window Manager, the hints they
use are somewhat alien to Fvwm pure. Hence, the freedesktop.org people
define EWMH (extended window manager hints). These essentially allow you
to run embedded apps like WMapplets, the KDE kicker, etc.
But I cannot be anymore specific than that since you don't say what is
happening. I'm not even sure if WM* apps use EWMH.
Thanks for the pointer. I'll browse their site when I get the time.
From reading the fvwm docs, I don't really understand the concept of
hints, from what you're saying here. My understanding was that they
are window properties containers (of sorts) which pertain to such
minor things as border shadowing.
[Thomas]
Kind of. EWMH hints are an unofficial extension of ICCCM 2.0 which the
freedesktop.org team have developed. Essentially, this implies the use
of KDE and GNOME, and allows for their own 'embedded' features to be
used with Fvwm if needed, since Fvwm is EWMH-compliant.
But what are EWMHs? They simply allow the interaction between
window managers, applications and the utilities that form part of a
desktop environment. This was originally written to replace Gnomehints.
And as such it has been implemented in GNOME >=2 and KDE >=2
AFAIK, WM* apps are not. Indeed, you can check this for yourself. If you
want to know whether an application uses EWMHs then do:
[n6tadam@station n6tadam]$ xprop | grep _NET_WM_STRUT
_NET_WM_STRUT(CARDINAL) = 0, 0, 0, 2
Here, the numbers indicate the screen space that the application in
question is using. Thus, you can "filter" out that area of the screen so
that an application window doesn't obscure it when maximising it. To
achieve that, one can use:
EWMHBaseStructs 0 0 0 2
In their ~/.fvwm2rc file. Why am I telling you this? I don't know
really, but it is just useful, since it can also be applied to
FvwmButtons.
To go back to your original question though, "hints" are just that --
properties of windows that can be configured or acted upon in some way.
Indeed, You can use a combination of things. It really depends
on how you want them gathered. You can define an IconBox for icons
minimised, with will place them in a region of the screen.
Also, since I installed SuSE 9 on this laptop (fvwm2 ver 2.5.7), the
buttonbar no longer works with swallowed apps. Have you run into any of
that? I still haven't visited the
Lately I read the fvwm stuff from issue #3 and discovered a few things
that had escaped me, and a few I'd forgotten about, like the ability to
drag windows between VD's via the pager.
[Thomas]
FvwmPager can do more than you probablu realise. As you say, you can
drag windows to other VD's and pages without even seeing the window
directly.
Also, from what I could gather by reading the fvwm man pages, it
seemed to me that they state that buttons in the buttonbar are pretty
limited in functionality, (e.g., toggled state like coolmail). I hope
I'm simply misunderstanding the issue, and that it is possible to put
a fairly complex applet like wmmount inside of the buttonbar.
[Thomas]
But of course! One can quite literally do anything with fvwm.
Ironically, what lets it down is the sheer volume of all the possible
things it can do.
As an example, if you wanted to have wmmount swallowed by FvwmButtons,
and then issue a command to it such that clicking on it mounted a
device, and then umounted it, you can do something like the following,
assuming you have the icon/applet swallowed:
AddToFunc ToggleMount
+ None (Mount, CirculateHit) Exec exec xterm -T Mount -n Mount -e mount $0
+ I Iconify
+ I Next (Mount, CirculateHit) Close
+ I Exec exec umount $0
Then from within FvwmButtons:
*FvwmButtons: (Action ToggleMount)
This might be long-winded, and indeed, the facility of wmmount might
even provide this mechanism, but it demonstrates what can be done. I
should point out that I haven't tested it, but it ought to work.
As old as it is, from my
viewpoint, there are still some aspects to fvwm that other wm's never
caught up to. IMO, it's a good compromise between lightweight and the
heavier DT environs like KDE and Gnome. However, the cfg process is
pretty much manual via edit of .fvwm2rc
[Thomas]
And I hope it stays manual. There are some 500+ style options for Fvwm.
There is no way one can enumerate this for a GUI. You wouldn't be able
to convey the options to the user efficiently.
I did look, and even suggest this at one point, but I have come to the
arrangement that it really is not a viable thing to do. There is always
the dotfile generator, but this is hideously out of date, and I really
do not suggest you use it.
John, if you like, upload your ~/.fvwm2rc file (or send it to me via
e-mail) and I will have a look at it and fix it for you. I'll also
change the syntax to conform to 2.5.X should there be any discrepencies.
Thanks, I'll probably take you up on the offer. I've spent 3 or 4
hours trying different things, without success.
[Thomas]
Then I am more than happy to go through it. I'll even throw in some
comments and explanations en route.
[Thomas] Well unfortunately John never did reply. But seriously, Fvwm is not as
cumbersome as it first seems, and if you really don't like MWM (which
has been labelled as butt ugly by a certain man wearing Dark
Sunglasses....
) then you can see what can be done with a little
effort here:
http://www.fvwm.org/screenshots/desktops
[Heather]
Ok, I'm late to the thread, but I concur there are some very cool things
you can do with this stuff. For a push in the right direction, I'm
including my own configuration, which Thomas helped me with, because a
lot of the tricks I was using on my own are from Ye Olden Fvwm 1.0 days,
and it needed a nice touch-up.
All of these parts go in a .fvwm directory under my home, which happens
to be /home/heather. So you'll find yourself going into these files and
changing at least that burned in location... unless your username happens
to be heather. The dotfile really has to be a dotfile, and take the
.txt extension off, of course.
Now for the warning label. I have great color vision and my monitor is
really bright, so my config is very dark. If you vision isn't as good
as mine, or your monitor isn't as vibrant, consider replacing the darker
blue with the rgb.txt named color NavyBlue or MidnightBlie. They just
weren't Navy or Midnight enough for me
I use a simple starfield
background. I actually cooked this one up years ago, back when I still
lived fulltime on (gasp!) Windows95. There was this great poster I
liked, and I kind of took a look at it then did a starfield of my after
the manner of it, except of course mine didn't have any things flying
around in front of it like theirs did, and mine tiled in a friendly
fashion, and for the sake of memory, didn't have that beautiful range of
gradient color. Feel free to go get your own bit of darkness from an
astronomy site, if you prefer.
See attached heather.stars16a.xpm
Everything is based around the .fvwm2rc file. In older flavors of fvwm
that was expected in your homedir, but now it's expecetd in ~/.fvwm
directory instead, to support you having a batch of extra parts.
The sneakiest thing in this is the trick to make the button which
invokes sticky status, change appearance permanently for a stuck window,
and change back if it's unstuck. My thanks to Thomas for showing me the
events interface.
See attached heather.dot.fvwm2rc.txt
I do some seriously strange things with my buttons layout. Seems like
every distro I ever looked at has a giant googly pair of Xeyes chasing
the cursor around, but I think they need to not be so huge. I do like
having a load monitor, but it doesn't look good if it doesn't cover the
full height. So some juggling is called for,
The buzzword for making "live" apps like Xeyes and xload stay involved is
a swallowed app - it doesn't need to be designed as an applet, it just has
to submit safely to having its geometry resized.
I love
icons but frankly I can find better things to do with some of my screen
estate, so maybe I want a few, but for some common tasks I use smaller
icons than others. I like a system load check but not taking too much
space, and I really abuse multiple pages, definitely preferring that
instead of multiple workspaces (though Fvwm supports those too).
Caveat for those with fancy video cards - you want workspaces (like K
desktop favors) or pages (like I do), not bigger virtual screens (controlled
in XF86Config-4). Sliding around looking for where the real
center of the screen is and wondering where you lost your control corner
or iconbox are not the way to spend your workday. My pages have a 2x4
layout, for 8 pages total, and this has generally been plenty for me.
See attached heather.ConfigFvwmButtons.txt
Unless I configure that darn pager explicitly, though, it comes out
pasty white. Agggh! My poor vampiric eyeballs. Again, if your color
vision likes brighter colors, or you hate purple, pick something
brighter from the named colors in rgb.txt. I used here, the "brighter"
NavyBlue, because the pages are tiny enough I wanted better contrast.
You might want them brighter yet, and make it just plain Blue.
There's a nice app named xcolors that will show all the colors for
you, i but you have to launch it with extra window page space already
available below ypur active window, because the window is too tall
(showing every color takes some space) and it's too stupid to have
a scrollbar. There's a gtk app that does a cleaner job of showing the
colors but I forget what it's called.
See attached heather.ConfigFvwmPager.txt
The sparkling touch of color on my active window is thanks to me using s
few tiny pixmaps instead of MWM-like vector corners. For the inactive
window I still use the vectors - they're faster, and they don't look
bad (I do wonder if I should do something cuter for sticky, but I've
been lazy). I got these from the fvwm95 icons kit, but for sanity and
portability, I copied them into .fvwm/icons, a directory.
Sticky means, it will "go" with me. I like that, bad puns in a tiny
setting...
See attached icons.mini-go.xpm
Ironically the icon that looks like a box, so is nice for maximize, is
named iconify.
See attached icons.mini-iconify.xpm
If it's stuck to the window, it looks vaguely like a 4-color windows icon.
See attached icons.mini-icons.xpm
dot in box for max, dot with no box for iconify.
See attached icons.mini-rball.xpm
X for eXit works for me.
See attached icons.mini-x.xpm
Of course the window controls belong to the window manager, so mentioning
that for the menu ocrner...
See attached icons.mini.fvwm.xpm
Last but not least, I have a couple of personal menus. One gives me
access to a number of differently colorized Xterms; I use them so much
color helps me recall which one's which even when I forget to retitle
them.
The other makes it easy to pop up web browsers, since I like to view the
world from different angles sometimes. "Netscape" on there is the
somewhat ancient Netscape 4.77 -- Netscape 7 and Mozilla don't seem to
be good neighbors, they keep stepping on each other's config files. I
use NS4 to spot buggy HTML code, because it has just horrid rendering when
the code's wrong and it sticks out like a sore thumb. Lynx I just
happen to like 'cuz it's speedy.
See attached main-nenu.heather.txt
Did I miss anything? Oh of course. A
screen shot
It's a bit on the large side, but I told you I had a big monitor.
That dark shot of the GIMP is also a goodie of mine, a GTK theme I
whipped up for myself which I call DarkGems, because I stole gemlike
features from a half dozen E and GTK themes. But this is about Fvwm,
not about GTK, so I'll save that for another time.
I also applied a minor hack on fvwm to not stipple my sticky title bars.
For most folks I think it'd be more a pain to recompile fvwm just to
leave that out, and then want to keep up to date, so I'll leave that out
too. It was in icons.c and the borders.c if you feel adventuresome.
Just making your desktop a little more fun ...
This page edited and maintained by the Editors
of Linux Gazette
Copyright © its authors, 2004
Published in issue 104 of Linux Gazette July 2004
Published in Issue 104 of Linux Gazette, July 2004
News Bytes
By Michael Conry
|
Contents:
|
Selected and formatted by Michael Conry <
>
Submitters, send your News Bytes items in
PLAIN TEXT
format. Other formats may be rejected without reading. You have been
warned! A one- or two-paragraph summary plus URL gets you a better
announcement than an entire press release. Submit items to
Linux Links
The Father of ASCII dies A tribute to Bob Bremer, one of the greats of the computer industry.
The Making of BSD Hacks describes one way to do open source revision control and document creation for book publishing.
relink, a package management tool.
Optimization complexities explored.
Thin GNU/Linux clients find application in libraries.
ACM Queue magazine focuses on open source.
Setting up encrypted partitions under Linux and dm-crypt.
How to talk to Microsoft about Linux
How to do due diligence
Open Source publishing
Embedded Processor and System-on-Chip Quick Reference Guide
News in General
Sun's Looking Glass
Sun have announced that they are releasing Project Looking Glass, their 3D desktop, under the GPL. This follows the release of JDIC (JDesktop Integration Components) under the LGPL. JDIC allows Java developers to write desktop software, including viewer components, screen savers, and panel applets.
Real/Helix
Real have anounced that they are adding the GPL as a licencing option
for Helix Player, making it fully open source.
Distro News
Skole
Skolelinux is a distro from Norway aimed to be a counterweight to the dominance of closed-source software in education and government.
Cobind
OSNews review of the Cobind distribution. This is a Fedora-derived distribution aimed at newcomers to the GNU/Linux scene.
Debian
It has been reported that the AMD 64 port of Debian is now ready for inclusion in unstable. (courtesy DWN)
Software News
Snort
O'Reilly has announced the publication of Snort 2.1 Intrusion Detection, Second Edition. This book provides a guide to the use of Snort, and in particular details the new features introduced in version 2.1. A CD-ROM is included containing Snort 2.1 and related utilities.
Mozilla
The Mozilla Foundation has announced the release of new versions of:
OpenOffice.org
OpenOffice.org has announced the availability of the new 1.1.2 version of the open source office suite, codenamed Hakone.
Mick is LG's News Bytes Editor.
![[Picture]](../gx/2002/tagbio/conry.jpg)
Originally hailing from Ireland, Michael is currently living in Baden,
Switzerland. There he works with ABB Corporate Research as a
Marie-Curie fellow, developing software for the simulation and design
of electrical power-systems equipment.
Before this, Michael worked as a lecturer in the Department of
Mechanical Engineering, University College Dublin; the same
institution that awarded him his PhD. The topic of this PhD research
was the use of Lamb waves in nondestructive testing. GNU/Linux has
been very useful in his past work, and Michael has a strong interest
in applying free software solutions to other problems in engineering.
Copyright © 2004, Michael Conry. Released under the
Open Publication license
unless otherwise noted in the body of the article. Linux Gazette is not
produced, sponsored, or endorsed by its prior host, SSC, Inc.
Published in Issue 104 of Linux Gazette, July 2004
Using Windows Keyboard Media Buttons In Linux
By Tom Brown
A lot of people making the move from Windows to Linux have a Windows
keyboard with extra buttons along the top. Some of these buttons control
the browser, while others control audio/video playback. As many have
already discovered, these buttons don't work in Linux. At least, they don't
by default.
The problem with these buttons is that, while they communicate with the
computer via keycodes like the regular keys, these codes aren't standard
ASCII. For example, the Microsoft Natural Keyboard Pro uses two keycodes
for each button press. The first code is a flag to indicate that the next
one will identify which button was pressed.
The process I'm going to describe is taken from KDE version 3.2.
Versions prior to that lack the interface to KHotKeys that the latest one
has.
Identify Your Keyboard to KDE
The first step is to make sure your keyboard is properly identified to
KDE. Go to the KDE Control Center - you'll find it listed in the "KMenu"
(click the icon where the "start" button would be in Windows). Once the
Control Center is up and running, click the "Regional & Accessibility"
(or similar - it may be called "Accessibility" in other Linux distributions
- Mandrake, for example) icon in the left-hand panel, the contents of which
will change. From this new list, select "Keyboard Layout". Now on the
right-hand panel, go to the "Layout" tab, and make sure the "Enable keyboard
layouts" check box is checked. Pull-down the "Keyboard model" combo list box,
and select your keyboard. It may originally say something like "Generic
101-key PC". You'll find a lot of keyboards listed, from a lot of
manufacturers, so hopefully yours will be in there. In my case, I selected
"Microsoft Natural Keyboard Pro / Microsoft Internet Keyboard Pro".
Now comes the fun part. With your keyboard properly identified, KDE will
now recognize those extra keyboard buttons when you press them. All you
have to do is tell it how to translate them into the proper action. The
technique I'm going to show you involves a KDE program called "KHotKeys".
Some people recommend that an action like changing the audio volume is more
properly done using the program "KMix" (a sound mixer). Unfortunately, this
didn't work in my case. Every time I raised and lowered the master volume
in KMix, instead of controlling the volume on my Sound Blaster Live card,
it made funky changes to the tone. YMMV. If KMix works fine for you, then use
it for volume control. The other reason I did it my way, and ignored those
recommendations, is that I wanted all of my changes in one place.
KHotKeys
You currently have "Keyboard Layout" selected in the KDE Control Center
list on the left-hand side of the screen. Move the mouse to "KHotKeys" at
the bottom of the list. If this isn't anywhere in the list, make sure you
are using KDE 3.2 or later (the version of KDE you're running will appear
in the right-hand panel of the Control Center when you first open it up).
Click on "KHotKeys", and the right-hand panel will contain the KHotKeys
configuration screen.
KHotKeys is a powerful program that allows you to define actions
corresponding to certain keystrokes. It also allows you to assign actions
to mouse gestures. We're interested, however, in how to assign an action to
a keypress - and, by extension, to the press of one of those media buttons.
Running a Program
We'll do something simple first. Many keyboards have a button marked
"Mail". We're going to define an action for that button so that it launches
Mozilla's email module. First, click the button marked "New Action" at the
bottom of the config screen. Under "Action Name" in the "General" tab,
replace "New Action" with something easy to remember, like "Mail".
Pull-down the "Action Type" list box, and select "Keyboard Shortcut ->
Command/URL (simple)". Make sure the "Disable" checkbox is empty. Enter
anything you want in the "Comment" box. Go to the "Keyboard Shortcut" tab,
and click the mouse in the tab's only button. You'll see a dialog box.
Press the "Mail" button on the keyboard, and the dialog box goes away. With
my keyboard, this results in the button displaying "XF86Mail". Go to the
"Command/URL Settings" tab. Enter the command line to be executed,
including the full path, and any arguments. To run the mail module of
Mozilla 1.6 on my machine, I used the following command:
/opt/mozilla/run-mozilla.sh /opt/mozilla/mozilla-bin -mail
Depending on what program (or shell script) you're running, the command
could be more or less complicated than this. If I just wanted to run the
Mozilla browser (for the "Web/Home" button, for instance), I would have
used:
/opt/mozilla/mozilla
Using DCOP to Control a Running Program
DCOP, or Desktop Communications
Protocol, is a generic way for applications to communicate with one another.
You have seen this sort of thing in Windows, which uses a technology called
OLE Automation (a part of "COM", or "Common Object Model"). DCOP is the method
we will use to send commands to an already-running program.
From the "General" tab of KHotKeys, create a new action, and set the
"Action Type" to "Keyboard Shortcut -> DCOP Call (simple)". From the
"Keyboard Shortcut" tab, identify the button you want to use, just as you
did with the previous example. Next, the "DCOP Call Settings" tab may seem
a bit confusing if you've never worked with DCOP before. At the bottom of
the tab is a button labeled "Run KDCOP". Kdcop is a GUI application that
allows you to browse the callable functions exposed by all running DCOP
applications in a standard tree view. Click the button to start kdcop.
Start the program you want to control, locate its name in kdcop, and click
the plus sign icon next to the name to expand it.
For this example, I'm going to use Jukebox (or "Juk"), an audio player
that comes with many Linux distributions. When you expand the entry "juk"
in kdcop, you see five entries. For this example, we want the one named
"Player". Expanding this "Player" node, we see a long list of supported
function calls. Now all we have to do is find the things we want to
control. Let's say we want the button to start juk playing music. Scroll
down the list until you see "void play()". That looks like programmer
stuff, doesn't it? Don't worry, you don't have to know what it all means to
make use of it. It's easy.
Copy the top tree entry (in this case, type "juk") into the "Remote
application" box. Then, copy the next node entry in the tree (in this case,
type "Player") into the "Remote object" box. Finally, copy the command,
without the "void", or the parenthesis (in this case, type "play") into the
"Called function" box. Note that all of these are case-sensitive.
Both kdcop and the KDE Control Center support drag-and-drop, so you
could also click and drag "void play()" to the KHotKeys window, and drop it
on any of the edit boxes. This results in "dcop juk Player play " (note the
trailing space) being pasted into the edit box. This is an easy way to get
the three entries you need for the "DCOP Call Settings" tab. In this
example, type "juk" into the "Remote application" box, "Player" into the
"Remote object" box, and "play" into the "Called function" box. Now, if you
did this the way I did, and dropped everything into "Called function",
deleting everything up to the word "play", then you made the same mistake I
made as well. For some reason, the system adds a space to the end of the
text, so the system looks for a command called "play " instead of "play",
and the button won't work. Using drag-and-drop here is more trouble than
it's worth, in my opinion. It would be nice if you could just drop the
entry onto the tab, and have it populate all the fields for you, but that's
not how it works right now.
Translating a Button into a Standard Keypress
If the application you're trying to control doesn't support DCOP, then
you have to simulate the pressing of a specific key combination on a button
press. For example, if you're using Mozilla 1.6, you can't use the DCOP
method to control the browser. Fortunately, you can convert a button into a
standard keypress that Mozilla understands. Once you have created a New
Action for KHotKeys, select an "Action Type" of "Keyboard Shortcut ->
Keyboard Input (simple)" from the pull-down list box in the "General" tab.
From the "Keyboard Shortcut" tab, identify the button you want to use, just
as you did with the examples above. On the "Keyboard Input Settings" tab,
enter the keystrokes you want the button translated to. Special keys have
to be spelled out. For example, to display your Home Page in Mozilla 1.6,
you hold down the "Alt" key, while pressing the "Home" key. You type this
into the "Keyboard input" field as (without the quotation marks, and
without any spaces): "Alt+Home". Warning: this button-to-key translation
doesn't care what application you're in. Think about what you're doing
before you assign the keyboard input to avoid unexpected results. Note that
this isn't limited to one keystroke. You could use "Hello World" if you
wanted to.
![[BIO]](../gx/2002/note.png)
Tom has been a software developer since the early days of the Commodore 64,
with such commercial classics as Prototerm-64 and Colorez-128, and has seen
lots of operating systems come and go. Every one he's liked is either
discontinued (OS/2) or out of business (Commodore Amiga). He currently likes
Red Hat Linux, which won't be supported after April '04. As a result, we've
been trying to get him to fall in love with Windows, but so far no luck.
Copyright © 2004, Tom Brown. Released under the
Open Publication license
unless otherwise noted in the body of the article. Linux Gazette is not
produced, sponsored, or endorsed by its prior host, SSC, Inc.
Published in Issue 104 of Linux Gazette, July 2004
How To Make a StereoGram with GIMP, Blender and StereoGraph
By Kapil Hari Paranjape
1. Introduction
Do you see what I see?
Single Image Stereograms (SIS) are two-dimensional images that seem to be
three-dimensional; these 3-d images appear to "pop up" (or "pop down") out of
the printed paper. The amount of training the typical human nervous system
requires to see such images seems to vary from person t
